Artificial breathing machine



Feb. 24, 1953 K. B. woLFE ARTIFICIAL BREATHING MACHINE 2 SHEETS-SHEET l Filed Sept. 20, 1950 INVENTOR.` KENNETH B. wou-E y WMI/ AT/TORNEYS m Feb. 24, 1953 K. B. wou-E ARTIFICIAL BREATHING MACHINE 2 SHEETS-SHEET 2 Filed Sept. 20, 1950 FIG lga

../lflll INVENTOR. KENNETH B. WOLFE FMI-3 ATTORNEYS place there. .machine Ahas its sole outlet II through a fitting Patented Feb. 24, 1953 UNITED STATES PATENT OFFICE ARTIFICIAL .BREATHING MACHINE .Kenneth B. Wolfe, Willoughby, 4Ghia Applioationseptember 20, 1950, Serial No. 185,756

(Cl. Sil-52.6)

`6 Claims. l

v"Iliis invention'relates 'to improvements'in an :aL-rticial breathing machine.

One of the objects of the present invention is toiprovide artificial means for reproducing the pressure pattern of an inhaling-exhaling cycle of the fhumanlungs in connection with a gas or anesthesia machine used to maintain the operation Iof "apatients lungs while on an operating 'table or vthe like.

'Another'object of the present invention `is to provide an artificial breathing 'machine comprising'a flexible bag having an -outlet to a lungconnected systemand `including means for positively contracting and expanding the bag by means of a cam which reproduces the pressure pattern of a typical inhaling-whaling cycle of the human lungs.

Another object of thepresent invention is the provision of an articial Abreathing machine Yadapted to `reproduce the normal breathing cycle of the human lungs and including means for driving the mechanism at various rates so as to coordinate the action of the machine with the desired action of the patients lungs.

Other objects and advantages of the present invention will beapparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings- Fig. lis a sectional view taken generally along the Vlines "I-I of Figs. 2 and 3 with partsbroken away to more clearly show Athe construction;

.Fig.i2 is a transverse sectional view taken along Fig. 3 isa transverse sectional View taken'along .the line 3-3 of Fig. l with parts broken away to `more `.clearly Ashow vthe structure.

My improved artiiicial breathing machine is shown in an embodiment designed for use with a standard gas or anesthesia machine of a known character wherein a closed system includes the lungs of the patient, a source of supply for air or a mixture of air and oxygen with or without the addition of anesthetic agents, and generally including a soda-lime chamber `for the absorption of carbon dioxide from the closed system. Such a system is substantially closed even 'though the tracheal tube in the patients windpipe is sealed by means of a cuil and slight leakage might take The flexible bag I!) ofthe present connected with tubing I2 which connects with the closed :system above described including the pa- 'ttents lungs. Normally, the tubing I2 is connected to 'the bottom of the sodallime chamber.

AFor mounting the `improved mechanism of the present invention I provide a base I3 formed Aof suitable structural steel members welded together and supported on legs ifi which contain casters for portability. `Across the central portion of the base there is xed a horizontally extending plate I5 as clearly shown in Figs, 1 and 3, Two "vertically extending plates I6, ita. are supported at opposite sides by means foi'the vertical structural angles I'l welded tothe plates I5, Ita. Angles 'I1 are welded to plate I5 at the bottom. vA U-shape bracket lil, as `bestseen in Figs. 1 and 2, is bolted to the angles Il and is secured to the litting II previously mentioned so as to support `it rigidly. The upper' end of the vertical frame Iii-l'l is braced by means of aistructure which comprises a strap i9 rigidly connected at its lower end to the base I3 and extending upwardly along the 'left side of the machine as shown in the various views, then bending horizontally along the portion 19a at the top of the machine, which portion is rigidly secured to a crossbar 2o 4which in turn is rigidly secured to the parallel. arms 2 I, which in turn are welded to the upper ends of the angles Il andthe plate It. The entire machine is surroundedby a cabinet 22 and between this cabinet and the various portions of theirame there are interposed spacer blocks 23, each of which comprises a metal piece Eta on each `side of which there is a layer of rubberdike material 23h so that vibration of the machine will not be reproduced in the walls ofthe cabinet. Each of the blocks 23is secured to the frame by means of a bolt or other securingmeans not shown.

Abutments are furnished-above and below the flexible bag l0 with means for causing relative appro ach and separating movementof `these'abutments so as to control the movement of the bag. In the present instance, above the bag I ll there is provided a `liked abutment 2li comprising a circular metal plate 'having a fixed central stem `25 which passes upwardly through a bracket '2'6 which in turn is bolted at 2l to the plate IG. Below the bag Ill there is a movable abutment 2B comprising a round plate fixed to a depending stem Sie which is supported in a suitable bracket 38 which is bolted to `pla-te lila at 3|. Suitable bearings 32 are provided in the bracket 31B to support the stem 29 for `relatively irictionless movement, On the lower end of stem 29 is rotatably mounted a follower 33 for a purpose presently to be described. l For securing theadvantages of positive movement of the'bag 1l El as will be presently described.

We preferto secure the bag lll tothe abutments Y 24 and 28 in a positive manner. Each abutment is provided with a flexible covering 24a and 28a respectively covering the side of the abutment adjacent the bag and extending over onto the opposite side of the abutment for security. Where the bag I is of rubber-like material, the coverings 24a and 28a are of similar material which is bonded or vulcanized to the ilexible bag I0 over the area of the respective abutments.

As best seen in Figs. 1 and partly broken away in Fig. 3,Y diagonal braces 34 and 35 extend upwardly from the base I3 to the plate I 6e, approximately opposite the top of the bracket 30 so as to firmly support the bracket 30 and the attendant mechanism for operating the bag. The-se braces are welded to the parts at their opposite ends so as to make the entire structure rigid.

The means here provided for reproducing the pressure pattern of an inhaling-exhaling cycle of the human lungs comprises a cam 36. This cam is shown in Fig. 1 inthe position where abutment 28 and stem 29 and follower 33 are in their lowermostposition and means to be later described is provided for rotating the cam 38 in the direction of the arrow A of Fig. 1 whereby the cam engages the follower 33 to lift the stem 29 and abutment 28 to the dot-dash position of Fig. 1 so as to compress the ilexible bag I0.

The cam 36 must be constructed very carefully so as to reproduce the natural action of the human lungs. The cam is attached to a shaft 31 and is rotated in the direction of the arrow A as previously mentioned. Starting at the position of Fig. 1, the cam very shortly contacts the follower 33 at approximately the point B. The continuing motion then raises the stem 29v `and abutment 28 as the cam traverses the portion from the point B to the point C. This bag compressing operation takes approximately 180 degrees of cam movement. That portion of cam 38 between points C and D is on an arc about the center of shaft 31 and therefore during this period of cam travel the flexible bag I Il remains stationary in the dot-dash position of Fig. 1. C'am travel from the point D to the point E results in the lowering of abutment 28 and stem 29 from the. dot-dash posif tion of Fig. 1 to the full line position. It will be noted that this expansion of the bag I is allowed to occur much more rapidly than the contraction of the bag which occurs between the points B and C on the cam. This bag expansion operation takes approximately 30 degrees of cam movement from D to H for slow expansion, and approximately 75 degrees of cam movement from H to B for sudden expansion movement. rThe cam traverses the angle F between points C and D which is approximately 75. Counting a few degrees on each side of the points C and D where very little motion of abutment 28 takes place, the result is that the iiexible bag I Il remains in its contracted or dot-dash position for approximately onequarter of the complete cycle.

Means is provided for rotating the cam 36 constantly so as to repeat the cycle described above. In the present instance, this means comprises an electric motor 38 which drives a V-shape pulley 39 which is of a known type made in two halves yieldably urged toward each other by a spring in the housing 40. A V belt 4I connects pulley 39 to a pulley 42 which in turn is connected to the input shaft 43 of a speed reducing gearing in housing 44.l The shaft 31, previously mentioned, is the output shaft for this reduction gearing and on it is secured cam 38 for rotation with shaft 31.

Means is provided for moving motor 38back 4 and forth in a horizontal direction as seen in Fig. 1 so as to cause the V belt 4I to ride in various positions with respect to the center of pulley 39 in a known manner so as to vary the speed with which motor 38 drives the pulley 42. To this end, the motor 38 is mounted on a base 45 which in turn is provided with brackets 4B embracing two guide rods 41 secured to brackets 48 on the base i3. A screw 49 is threaded into bracket 48 and mounted for rotation in a bearing 58 on one of the brackets 48. The other end of the shaft having the thread 49 has mounted thereon a bevel gear 5I which meshes with bevel gear 52 mounted on vertical shaft I3 for rotation therewith. This vertical shaft has bearings in brackets 54 at the bottom and 55 at the top. Bracket 54 is bolted to strap I9 and bracket 55 is supported in the strap portion Ita. The upper end of shaft'53 is supplied with a hand wheel 55. By turning hand wheel 56 when motor 38 is running, the screw 49 is rotated in its receiving bracket 48 so as to cause the motor'base 45 to move horizontally along the supporting rods 41. As previously mentioned, this is a known manner or" causing the V belt 4I to change its position relative to the center of pulley 39 so as to change the speed with which motor 38 drives the pulley 42.

Preferably, the movable base of motor 38 is provided with an indicating arm 51 extending to a point above a plate 53 on top of the cabinet. This plate is calibrated in terms of respirations per minute so that the machine may be readily adjusted for the number of respirations per minute ment 28 is moved to the dot-dash position of Fig.

1 there is created in the patients lungs and the closed system connected therewith a. pressure of around 15 millimeters of mercury or slightly less. The arrangement is such also that when the parts are in the full line position of Fig. 1 the pressure in the closed system including the patients lungs drops to about zero or even to a suction of a few millimeters of mercury. Motor 39, pulleys 39 and 42 and reduction gearing i4 are so chosen that the motor` may be set to drive cam 33 to produce the number of respirations per minute required for this duty. Normally this would be from about 14 to about 28 respirations per minute. Normally an adult will be given about 16 to 18 respirations per minute on this machine with children a little bit higher in the neighborhood of 20 to 22 respirations per minute.

The operation of our improved machine should now be readily understood. With the tubing I2 connected to the gas machine as previously described, the machine is set in motion by a supply of electricity to motor 38 from a source not shown. The hand wheel 59 is set to provide that number of respirations per minute required by the patient under consideration. The bag I 8 will then be given regular expansions and contractions according t0 the pattern of the earn The lungs will first be lled slowly, then held filled for approximately 25% of the cyclev and then more rapidly allowed to collapse or'exhale.

As an illustration of a cam adapted to reproduce a suitable action in the human lungs, I may state that the cam 38 has a periphery from B to C comprising the arc of a circle of Za inches radius about the center G. From C to D, the cam is constructed on a radius of 3% inches about the center line of shaft 3l. From D to H, the cam has an arc of about 1%, inches radius about the center J and the points H and B are connected by a straight line.

I prefer to allow the follower 33 to clear the cam 36 slightly in the full line position of the parts in Fig. 1 so as to be certain that the bag Ill is fully expanded at this point. The weight of the stem 29 and connected parts are sulicient to return the flexible bag downwardly from the dot-dash position to the full line position of Fig. 1. A spring might be provided to aid in this movement if desired. However, there is normally ya residual pressure in the gas machine which aids in moving the bag I0 toward the full line position of Fig. 1.

What I claim is: l

1. An articial breathing machine comprising a exible bag having an outlet, a frame, a pair of abutments on said frame on opposite sides of said bag, means mounting at least one of said abutments for movement toward and away from the other of said abutments, a cam having an operative connection with said movable one of said abutments, drive means operatively connected with said cam for rotating it, and said cam having a contour controlling movement of said bag to reproduce in said system the pressure pattern of an inhaling-exhaling cycle of the human lungs.

2. The combination of claim 1 wherein said abutments are secured to said bag, and means is provided for causing movement of said movable abutment away from the other of said abutments, whereby to induce an exhaling effect when said outlet is connected with a patients lungs.

3. The combination of claim 1 wherein said abutments are secured to said bagl and a Weight is connected with said movable abutment and acted upon by gravity to cause relative separation of said abutments, whereby to induce an exhaling effect when said outlet is connected with a patients lungs.

4. The combination of claim 1 wherein said abutments are positioned respectively above and below said bag, said upper abutment is relatively fixed, means' mounting said lower abutment for vertical movement including a bar extending downwardly, a bearing embracing said bar, and said cam engaging the lower end of said bar.

5. The combination of claim 1 including control means operatively connected with said drive means for setting the latter at any one of various speeds.

6. In an articial breathing machine comprising a flexible bag, and relatively movable abutment means engaging said bag on opposite sides to compress and expand said bag, the combination therewith of a cam rotatable continuously in one direction and operatively connected with one of said abutment means and controlling movement of said bag, said cam having a portion for compressing said bag steadily through approximately 180 degrees of cam travel, said cam having a next succeeding dwell portion for approximately degrees of cam travel, said cam having a next succeeding portion for permitting expansion of said bag through approximately degrees of cam travel, said last named portion being formed to rst permit slower expansion and to later permit faster expansion, and means for rotating said cam.

KENNETH B. WOLFE.

REFERENCES CITED The following references are of record in the nle of this patent:

UNITED STATES PATENTS Number Name Date 28,758 Lapham June 19, 1860 1,188,565 Severy June 27, 1916 1,998,616 Hamilton Apr. 23, 1935 2,063,043 McKesson Der;- 8, 1936 2,079,952 Sahlin May 11, 1937 2,292,527 Kraft Aug.. 11, 1942 2,309,470 McCollam Jan. 26, 1943 2,398,520 Clements Apr., 16, 1946 

